Starter control for internal combustion engines



Jan. 22, 1935. R. N. PATTERSON 1,988,958

STARTER CONTROL FOR INTERNAL COMBUSTION ENGINES Filed Oct. 24, 1932 IN V EN TOR.

ATTORNEY Patented Jan. 22, 1935 UNITED STATES PATENT OFFICE STARTER CONTROL FOR INTERNAL COM- BUSTION ENGINES Robert N. Patterson, Oakland,

cum, assignor to 12 Claims.

tion circuit is energized.

A general object of the invention is to safeguard the mechanisms controlled while providing a complete measure of control therefor.

Another object of the invention is to provide a means of the character described which is automatically and positively rendered inoperative while the engine is actuating.

A further object is to provide a starter motor control which is intermittent in its action while operative.

Yet another object is to provide the control means of the present invention in a single unit which is applicable as an attachment to usual electrical systems of internal combustion engines without necessitating any change in the essential apparatus of such systems.

The invention possesses other objects andpfeatures of advantage, some 01' which, with the foregoing, will be set forth or be apparent in the following description of a preferred embodiment of the invention, and in the accompanying drawing, in which,

Figure 1 is a sectional elevation of a unit providing the control mechanism of the present invention.

Figure 2 is a sectional view at 2-2 in Figure 1.

Figure 3 is a section taken generally at the stepped line 33 in Figure 1.

Figure 4 is a diagrammatic elevation showing the'present control means applied for the starting and stopping control of an internal combustion engine having usual electric circuits associated therewith.

Figures 5, 6, 7 and 8 are wiring diagrams showing four different combinations of current flow conditions which may obtain in the engine control circuits when the present unit is in use.

The control means of the present invention essentially comprises a unit 9 for installation in place of the usual switch for hand or foot opertion to open and close the power circuit of a starting motor for an engine. .As particularly illustrated in Figure 4, a unit 9 is shown in operafive association with a. direct-current starting motor 11 for actuating an internal combustion engine 12 utilizing an ignition system including spark plugs, said system and its parts being indicated generally by the numeral 13. A directcurrent generator 14 is associated with the engine for actuation therewith to deliver power to a storage battery 15 through a circuit including an automatic cut-out switch 16, said battery providing the energy for the ignition and motor circuits in a well known manner and being shown as grounded at its negative side. In the present instance, the engine 12 is assumed to be. that of a self-propelled motor vehicle, though the use of the control unit is not necessarily limited to engines so applied.

By particular reference to Figures 4 to 8 inclusive, it is noted that the ignition system 13 is grounded at its negative side and is connected to the positive side of the battery 15 through a conductor wire 21, a switch 17 mounted on the instrument board 18 of the automobile (not shown), and a conductor 22. The motor circuit also starts from the positive side of the battery 15 and includes a portion of the conductor 22, a conductor 23, a hereinafter described switch of the unit 9, the motor 11, and a ground connection 24. The generator, or charging, circuit includes a ground connection 25, the generator 14, a conductor 20, the cut-out switch 16, and a conductor 26 which is connected at-the positive side of the battery 15. It is noted that the switch 16 is arranged to close the circuitto the battery 15 only when the generated voltage of the generator exceeds the battery discharge voltage, thereby preventing a battery discharge through the generator when the latter is inoperative to charge the battery. Since the indicated structure and use of such automatic cut-out switches, or reverse-current relays, in battery-charging circuits is well known in the art, and the specific structure of the switch is immaterial to the present invention, the details of said switch are not herein disclosed.

A normally disengaged automatic clutch device 19 is provided for connecting the motor 11 with the engine following an energizing and starting of the motor, such devices being well known in the art.

The mechanism of the unit 9, it will now be noted, provides a switch 27 of a differential relay type wherein electromagnet coils 28 and 29 (Figures 1 and 5 to 8) have a common terminal 31 and under certain current flow conditions therein are arranged to magnetically influence an armature 32 to displace the same against the resistance of a spring 33 which normally disposes said armature out of a position thereof which it may assume when the field strength of the coils is sumcient to displace it.

The armature 32 is arranged to actuate an element 34, said element arranged to provide an electrical connection between relatively fixed and mutually spaced contacts 35 for connection in the power circuit of the motor; as particularly illustrated, the element 34 comprises a conductor carried by the armature 32 in normally spaced relation to the contacts 35 and arranged to simultaneously engage said contacts when the armature is displaced in the indicated manner. In the present instance the contacts 35 are provided in integral association with binding posts 36 and 37 fortgonnecting them in the power circuit of the mo r.

The unit 9 further provides a combined resistance and heating coil 38 which extends from a terminal 39 to the coil terminal 31 and encloses a compound thermostat bar 41. When the bar 41 is heated, it is arranged to provide a low-resistance connection therethrough between the terminals 39 and 31 whereby to then short out the coil 38; as particularly shown, one end of the bar 41 is held fixed at the terminal 39 in electrical contact therewith and the other bar end is arranged for movement into and from en agement with a contact 42 connected to the terminal 31. As illustrated, the bar 41 is normally curved away from the contact 42 and is arranged to straighten out for engaging said contact when sufficiently heated by the coil 38. .Binding posts 43, 44 and 45 are respectively provided at the terminal 39 and at the free ends of the coils 28 and 29 to provide circuit connections for the coils.

For operatively installing the control unit elements in association with the engine 12 and its associated electrical circuits, the binding post 36 is connected to the conductor 22 by means of a conductor 46, the post 37 is connected to a motor terminal through a conductor 47, the post 43 is connected to the conductor 21 through a conductor 48, the post 44 is connected to the conductor 20 through a conductor 49, and the post 45 is grounded through a conductor 51. It is noted that the circuit through the conductor 22, ignition switch 17, conductor 21, conductor 48, coil 38, coil 28, conductor 49, conductor 20, generator 14, and ground connection 25 comprises a primary control circuit for the switch 2'7 whereby a closing of the switch 1'7 is arranged to initially provide a current flow through the coils 38 and 28, reference being made to the diagrammatic showing of Figure 5. A secondary, and branch, control circuit is provided from the terminal 31 through the switch coil 29 and ground connection 51, it now being noted that the coils 28 and 29 are similarly and coaxially wound in their helices whereby the magnetic field thereof produced by a current flowing through them from their common terminal 31 is the sum of their individual fields.

Referring now to the operation of the control means and the current conditions in the control circuits, it is noted that when the switch 1'? is closed while the engine is inactive, the flow of current from the battery 15 is arranged to heat the thermostat bar 41 whereby the latter may engage the contact 42 for short-circuiting the coil 38 and thereby increase the current flow in the control circuit portions. The resistance relations of the circuit are such that the combined magnetic field of the'coils 28 and 29 is too weak to actuate the armature 32 for closing the switch 27 except when the coil 38 is shorted out of the circuit. The closing of the switch 27 energizes the motor 11 for turning over the engine 12 to start it.

By reason of the use of the coil 38 in operative association with the thermostat bar 41, it will be understood that the motor is not energized immediately upon a closing of the ignition switch 1'7, but that an appreciable period of time elapses before the motor circuit is closed through actuation of the armature 32; in this manner, time is given for a complete stopping of the engine before the starting motor is re-energized following a failure of the engine to be self-actuating, the latter situation arising when a starting effort fails or the engine'is stalled. The foregoing feature of delayed action, it is noted, safeguards the clutch device against damaging stresses and jerks.

Since the shunting out of the combined heating and resistance coil 38 deprives said coil of current for heating the bar 41, the latter will cool while acting as a short, and will finally open the circuit at the contact 42 whereby the coil 38 will again be energized for heating it. In this manner an intermittent action of the switch 27 will result until the engine is sta ted, thereby safeguarding the battery and givin the operator an opportunity to make any adjustments needed to aid in starting the engine. It will be under-- stood that the heating and cooling times for the thermostat bar 41 are primarily determined by the heat insulation and/or radiation conditions at the bar in its set mounting, and that said conditions are controllable. in association with the bar in its mounted position.

When the engine becomes self-actuating, the

current discharge from the generator 14 to the control circuit opposes the battery current in the circuit whereby the actual current flow through the coil 38 is arranged to become too small to cause the described short-circuiting action of the bar 41 through the heating thereof. Furthermore, when the generator voltage exceeds that of the battery, the magnetic fields of the coils 28 and 29 will oppose and neutralize each other and the switch 27 will remain open through action of the spring 33; preferably, the resistance of the coil 29 exceeds that of the coil 28, said coils having such numbers of ampere turns as will minimize their joint magnetic field when the generator voltage prevails in the control circuit. The foregoing operative conditions may apply "both before and after the cut-out switch 16 is closed by action of the generated voltage of the generator. In Figure 7, the indicated circuit conditions are those which exist while the engine is self-actuating and the generator is charging the battery. 4

The stopping of the engine may be effected by and upon an opening of the ignition switch 17. Although when said switch is opened, the generator may still be discharging into the control circuit and is therefore connected with the ignition circuit through the conductor 21, the resistance of the control circuit and the grounding thereof through the coil 29 are arranged to prevent a sufiicient current flow to the ignition circuit to provide for its continued operation. In this manner, the switch 1'7 alone provides the necessary starting and stopping control for the engine, and is operative as a master switch for the various circuits. It will be obvious that the switch 17 may be key-controlled whereby a starting of the engine by an unauthorized person may be prevented. The circuit conditions when the switch 1'7 is opened with the engine running are indicated in Figure 8.

By reference to Figures 1 to 3 inclusive, it will be noted that the various elements of the control unit 9 are provided in a particularly compact assembly including a cylindric and tubular cas-' ing 53 having closure discs 54 and 55 fixed at the opposite ends thereof. The binding posts 36 and 37 extend radially through and from the casing 53 at diametrically opposite points thereof, are insulated from said casing, and provide the contacts 35 at their inner ends. The movable switch element 34 comprises a disc slidably carried on a stem 56 extending axially from the cylindric 32 and through the casing end 54, and is displaceably held against the outer armature end by and a shoulder 58 of the stem, said disc insulated from the stem and spring, and the shoulder 58 normally engaging the end plate 54 to limit the outward disposal of the armature. A spool 59 is closely fitted within the bore of the casing 53 for mounting the coils 28 and 29, said spool slidably receiving the armature 32 in the bore thereof. As shown, the spool ends 61 and 62 engage the bore of the casing 53, and the ends 62 provide a fragmentary core 63 extending into the spool bore in opposition to the armature 32, the spring 33 being operativebetween said armature and core. The spool elements and the casing 53 are preferably all of magnetic material whereby to provide a closed magnetic field when a field is produced in the indicated manner.

A disc 64 is fitted within the casing 53 between the spool 59 and the closure disc 55, both of said discs preferably being of electrically non-conductive material and said discs being mutually spaced. As is particularly shown, the binding posts 43,

44 and 45 extend through the discs, and tubular spacers 65 are mounted on the posts and between the discs for providing a closed space in which the coil 38 and thermostat bar 41 are disposed.

Nuts of the binding posts secure the discs and 64 in relatively fixed relation, it being noted that the fixed end of the bar 41 is clamped between sections of the spacer 65 at the binding post 43. The inner disc 64 mounts the contact 42 and the common terminal for the coils 28, 29 and 38. The coil 38 is, of course, suitably insulated from the bar 41, and the disposal of the bar in the casing space provided therefor will tend to control the radiation thereat whereby the described actuations of the bar through its heating and cooling will not occur too quickly. Preferably, the aforesaid space would be vented through the end disc 55, as indicated at 66.

The present control unit is particularly designed for direct mounting on a starting motor, it being a general practice to provide such motors with at least one external terminal post 67 extending upwardly from the motor. Accordingly, the conductor 47 is shown as comprising a bracket bar of suitable shape and arranged to have one end thereof fixed to the control unit terminal 37 and the other end fixed to the motor terminal 67 whereby to support the unit and at the same time afford the necessary electrical connection for the motor.

From the foregoing description taken in connection with the accompanying drawing, the advantages of the construction and method of operation will be readily understood by those skilled in the art to which the invention appertains, and while I have described the principle of operation, together with the device which I now consider to be a preferred embodiment thereof, I desire to have it understood that the device shown is merely illustrative, and that such changes may be made as fall within the scope of the appended claims.

Having thus described my invention, I claim as new and desire to secure by Letters Patent of the United States the following:

1. In combination, a storage battery, a generator for actuation to charge said'battery, a motor for actuation by energy derived from said battery, a magnetically operable and normally open switch controlling the circuit of said motor and including an operating coil for the switch, a control circuit connecting said battery and generator through said coil and arranged to be initially energized from said battery, and means automatically actuable by a predetermined current fiow in the control circuit to decrease'the electrical resistance of said circuit from a normal value thereof whereby to increase the current flow therein, the magnetic field of said coil operative to close said switch only when said increased current fiow obtains therein.

2. In combination, a storage battery, a generator for actuation to charge said battery, a motor for actuation by energy derived from saidbattery, a magnetically operable and normally open switch controlling the circuit of said motor, a magnetic coil for energization to close the switch, a control circuit connecting said battery and generator through said coil for joint energization by opposing currents from the battery and generator, and means automatically factuable by a predetermined and timed current fiow in'the control circuit to decrease the electrical resistance in said circuit from a normal value thereof whereby to increase the possible current fiow in the control circuit, the magnetic field of said coil operative to close said switch only when the generator is inactive and said increased current fiow obtains in the control circuit.

3. In combination, a storage battery, a generator for actuation to charge said battery, a motor for actuation by energy-derived from said battery, a magnetically operable and normally open switch for closing the circuit of said motor and including a switch-operating coil, a control switch, a control circuit including said control switch and connecting said battery and generator through said coil, and means to automatically and temporarily decrease the electrical resistance of said control circuit from'a normal value thereof while the control switch is closed and by reason of the current fiow through the circuit, the magnetic field of said coil operative to close said switch only when the resistance of the control circuit has been decreased by said means.

4. In combination, an internal combustion engine, a storage battery, a generator for actuation by said engine to charge said battery, a starting motor for said engine and for actuation by power derived from said battery, a magnetically operated and normally open switch controlling the circuit of said motor, an operating coil for the switch, a control circuit connecting corresponding terminals of said battery and generator through said coil, and means operable to decrease the electrical resistance of said control circuit from a normal value thereof, said means comprising a heating coil permanently interposed in said control circuit and a thermostat member for heating by said heating coil and operative when heated to a predetermined degree to provide a low resistance shunt around said heating coil and thereby reduce the electrical resistance of the control circuit, the magnetic field of said switchoperating coil operative to close said switch only when the resistance of the control circuit is decreased by the aforesaid means.

5. In combination, an internal combustion engine, an electric starting motor for said engine, a constant-voltage source of current for supplying actuating energy to said motor, a magnetically operable and normally open switch controlling the power circuit of said motor and including a switch-operating coil, a control circuit including said current source and said coil, and means for actuation by an initial fiow of current from said source through said control circuit for decreasing the electrical resistance of the control circuit, the magnetic field of said coil operative to close said switch only when the resistance of the control circuit has been decreased by said means.

6. In combination, an internal combustion engine, a storage battery, a generator for actuation by said engine to charge said battery, 2. "starting motor for said engine and for actuation by powerderived from said battery; a magnetically operated switch controlling the motor circuit, means normally maintaining saidswitch in open condition, an operating coil for the switch, a control circuit connecting corresponding terminals of said battery and generator through said coil, a combined resistance and heating coil in said control circuit, a compound thermostat bar.thermally associated with said heating coil and arranged to electrically connect the terminals of the heating coil when sufliciently heated by the coil whereby to temporarily shunt out the coil and permit an increased current fiow in the control circuit, the magnetic field of said switch-operating coil operative to close said switch only when said increased current flow obtains in the control circuit.

7. In combination, a storage battery, a generator for actuation to charge said battery, an electric motor for actuation by energy derived from said battery, a normally open electromagnetic switch controlling the power circuit of said motor and having a pair of operating coils, and a control circuit including said battery and generator and switch coils in such manner that the joint magnetic field produced by the coils by reason of a current fiow therethrough from the battery is operative to actuate the switch to close the motor circuit and the joint magnetic field produced by the coils by reason of a current fiow therethrough from the generator is inoperative to closes the switch.

8. In combination, a storage battery, a generator for actuation to charge said battery, a motor for actuation by energy derived from said battery, a magnetically operable and normally open switch controlling the circuit of said motor, a pair of operating coils for said switch and having a common terminal, a control circuit connecting corresponding terminals of said battery and generator through a said coil, and a branch circuit connecting the second coil with the other terminals of said battery and generator, said coils having their common terminal at the battery connection end thereof and being correspondingly wound whereby the joint magnetic field of the coils resulting from a current fiow therethrough from the battery will be the sum of the magnetic fields of the coils and the joint magnetic field of the coils resulting from a current fiow therethrough from the generator will be the difference of the magnetic fields of the coils, said joint magnetic fields being respectively operative and inoperative to close said switch.

9. In combination, an internal combustion engine, a storage battery, a generator for actuation by said engine to charge said battery through a battery-charging circuit, ignition means for said engine comprising an ignition circuit deriving energy from said battery and including a manually operable switch therein, a starting motor for said engine and for actuation by energy from said battery through a motor circuit, a normally open difierential relay switch controlling the circuit of said motor and comprising a pair of coils having a common terminal, a control circuit connecting corresponding terminals of said batteiy and generator through said ignition switch and a said coil, a branch control circuit connecting the second coil with the other terminals of said battery and generator, said coils having their common terminal at the battery connection end thereof and being correspondingly wound, a combined resistance and heating coil interposed injsaid control circuit between the relay,.coils and ignition switch, thermostat means thermally associated with said heating coil and arran' cl to effect a low-resistance connection in the co' trol circuit for shunting out solely the heating coil when sumciently heated therefrom whereby to permit an increased current flow in the control circuit, said thermostat means operative only when the control circuit is energized substantially solely from said battery and said differential relay switch operative only when said increased current flow obtains in said control circuit.

10. In combination, a storage battery, a generator for actuation to charge said battery, a power circuit for receiving energy from said battery, a magnetically operable and normally open switch for closing said power circuit and including a switch-operating coil, a control circuit connecting said battery and generator through said coil and arranged for a continuous closed condition thereof, and means operated by the current flow therein to automatically decrease the electrical resistance of the closed control circuit from a normal value thereof, the

magnetic field of said coil operative to close'said switch only when the resistance of the control circuit has been decreased by said means.

11. In combination, a storage battery, a generator for actuation to charge said battery, a

power circuit for receiving energy from said battery, a magnetically operable and normally open switch for closing said power circuit and including a switch-operating coil, a control circuit connecting said battery and generator through said coil and arranged for a continuous closed condition thereof, and means operated by and in accordance with the current fiow therein to automatically change the electrical resistance of said control circuit from a normal value thereof to another value, the magnetic field of said coil operative to close said switch only when the resistance of the control circuit is at a lower value thereof.

12. In combination, a storage battery, a generator for actuation to charge said battery, a power circuit for receiving energy from said battery, a magnetically operable and normally open switch for closing said power circuit and including a switch-operating coil,a variable resistance means, a control circuit connecting said battery and generator through said resistance means and said coil and arranged for a continuous closed condition thereof, and means whereby the current flow through said control circuit is automatically operative to effect said resistance means to change the magnitude of the current in said control circuit from anormal finite value thereof to another finite value thereof, the magnetic field of said coil operative to close said switch only when the current of the control circuit is at the higher value thereof.

ROBERT N. PATTERSON. 

